^ Then just buy some tubing with an OD that matches the ID of your existing tube, or an adapter to reduce the size a bit less so it doesn't take as long. Since I don't know what sizes you're dealing with, this is just a generic link on amazon but you might also find some at hardware or auto parts stores:https://www.amazon.com/s?k=tubing+reducer&ref=nb_sb_noss
If you only have this ONE time use, you might be able to get by coupling two dissimilar size hoses with duct or electrical tape, or get a "few" uses if coupled with heatshrink tubing, or use caulking or whatever to seal them if you have time to let that set.
Vinyl tubing tends to be more flexible and seal (against another tube you slip it into) than some of hard plastic tubing types, and it helps visually that it's transparent. Some hardware stores sell it by the foot, I know my local mom 'n pop hardware store does but not sure about the big box stores. Checking Home Depot I do see 1/4" OD in 10ft length $3 but nothing smaller.https://www.homedepot.com/p/UDP-0-1...t-Clear-Vinyl-Tubing-T10006003/304185157
It's a bit conspicuous that you didn't mention what pump and tubing isn't working.